Galvanic cell separator

Abstract

A galvanic cell separator composed of polyvinyl alcohol having a crystallinity of 0.4 or more to be used with a galvanic cell containing alkaline electrolyte, and a method of manufacturing the same.

What we claim is: 
     
       1. A method for manufacturing a galvanic cell separator which comprises the steps of (a) heating a polyvinyl alcohol film until the polyvinyl alcohol has a crystallinity of at least 0.4 and subsequently   (b) contacting the surface of said polyvinyl alcohol film with an aqueous solution of permanganate.   
     
     
       2. The method as defined in claim 1 wherein in step (a) the polyvinyl alcohol film is treated until the polyvinyl alcohol has a crystallinity ranging from 0.5 to 0.6. 
     
     
       3. The method as defined in claim 1 wherein in step (a) the heating is carried in a non-oxidizing atmosphere. 
     
     
       4. The method as defined in claim 1 wherein in step (a) the heating is carried out at a temperature of from 130° to 240° C. 
     
     
       5. The method as defined in claim 1 wherein in step (b) the concentration of permanganate in the aqueous solution of permanganate ranges from 0.001 gram equivalent per liter to saturation concentration.